I figured to add another something we can do when we don't have energy: cooking. Just hear me out on this one.

Cooking will have it's tiers, depending on how much you cook and how successful you are at making it. When you first start out cooking, it will be "one star" and you will work up your way to "two stars" then "three stars" and up to "five stars".

Here's the process:

Haven will have a house entrance called the "Skylark Kitchen" which is a temporary kitchen from the Skylark. Biscotti will be there inside and will provide small missions and cooking recipes you can buy using crowns. Biscotti will ask you to level up your cooking by cooking your known recipes and new recipes you buy from her. In one mission, you will provide items you cooked yourself to her in order to advance to be able to cook "Two star" recipes.

So here it is in a nutshell for the learning process.
-Meet Biscotti in the kitchen. She will give you a couple of free recipes and will vendor the ones you can learn.
-Your cooking recipes will have a level. The higher the level, the more chance the cooking on that recipe will be a success.
-You will also have a "Cooking" level overall, which gives access to ascend and learn more recipes. Once you go up a rank, or level, talk to Biscotti and she will ask for some of your cooking. Giving her that, she will provide you with more recipes and allow you to go up another rank, or level.
-The higher the "star" number, the harder it will be to cook it.

So to balance it out so it wouldn't affect the economy? Well my suggstions:
-Recipes cannot be traded.
-Cooking items can be shared on the same account only. Meaning, cooking items you made will not be able to trade to players or drop. That means no auctionhousing cooking related things.
-Sorry this won't be like Missions where you get heat, crowns, items, and prestige.

So what are the buffs?
-Shock, Fire, Freeze, or Poison resist per item(The benefits will be lower than trinket items of course)
-Shadow, Elemental, Normal, or Piercing resist (Of course, less than trinket items)
-Shadow, Elemental, Normal, or Piercing attack boost (Again less than trinket)

Here are examples of food:

'Shock Jelly Taffy'
A chewy candy made from the shock jellies. It's Shockingly Delicious! (pun on Lucky Charms lol)

'Graveyard Stock'
A broth made from the remains of animal bones and zombie bones. Well, what else do you expect to eat in the middle of the graveyard?

I don't have any other ideas on recipe names...so yeah. What you guys think of the concept so far?

Questions and Answers

'For cooking to exist it must be clarified our knights are organic; as of now we are robots from space.'
Well...Biscotti was making cake and theres a quote from one of the recon knights saying "Good data is like good pudding. You can never have too much of it." So I assume they must eat a bit.

'Assuming our knights are organic, how would food be consumed and where would the effects go? Are they just UV stamps with preset buffs? Is cooking supposed to be a profession where players make items unrelated to equipment? Does this lead to crafting our own accessories? Are food buffs only in effect for a floor/mission?'
-Cooked items will be in "Usable" Category of the arsenal (Where Mist Tanks and Weapon and Trinket Slots go, etc).
-UV Stamps? Well...I guess you can call it "Temporary" UVs in a way, since they give a buff for a limited time. If you mean "Will the cooked items have UVs?", then the answer is no.
-Profession? Hmm...well I'm not sure so far. But yes the cooked items will NOT be related to equipment.
-There will be NO EQUIPS WHATSOEVER.
-For a whole mission, the food buffs will be enabled until you die. If you die, the buff disappears and you have to use another cooked item or deal without the buff. For floors in dungeon, it may be up to 2-3 levels. 4 levels would be too much.

'Professions/production skills create a whole new aspect of the game. It would make things more interesting but the problem is how it would be incorporated into the current mechanics without forcing the developers to overhaul everything.'
True but you know accessories right? They may figure out a way.

'I think it could be a nifty idea. But what would you do with it, it might be good as pop rocks that do an energy blast in front of you but beside that what would they do?'
Eh this will have nothing to do with attacks or anything. It's just a small buff...nothing more.

'Can you stack effects? For example, could you eat "Shock Jelly Taffy" and "Graveyard Stock" to combine their effects? Could you eat multiple pieces of "Shock Jelly Taffy" to further boost its effect?'
Here's an example...let's say "Shock Jelly Taffy" is a shock resist cooked item. There is another cooked item called "Shocky Tarts" that has the shock resist. Let's say "Shock Jelly Taffy" is a three-star cooked item. You eat that. You get the buff. "Shocky Tarts" is a two-star cooked item. If you eat that while having the "Shock Jelly Taffy" already eaten, then it will do nothing, since the buff is below that. Oh, and eating multiple "Shock Jelly Taffy" won't improve anything. So basically, no stacked buffs or anything. However, if you eat "Shock Jelly Taffy" and "Graveyard Stock" (let's say Graveyard Stock adds a health bonus), you will have both effects. To keep it balanced, however, you can only have three buffs from cooked items. If you eat a fourth cooked item that has a different resist than the three active, then it will remove the first one you ate.